A light emitting diodes (LED) is generally used as a backlight source in a typical liquid crystal display (LCD) device, a plurality of the LEDs are connected in series to form lightbars, and the lightbars are connected in parallel if there are two or more of the lightbars. The LED lightbar drive is controlled by a driver integrated circuit (IC). To ensure that the lightbars can safely and reliably operate, the driver IC generally has an input undervoltage protection and an output overvoltage protection function. However, in the prior art, the protection signals of the two protection schemes occupy two pins of the driver IC, which makes the driver IC not as useful when the pins are being used